Tape feeder, electronic component mounting apparatus using the same, and method of feeding electronic components

ABSTRACT

A tape feeder for feeding electronic components by advancing a tape intermittently, the tape feeder comprises a motor controller for controlling a motor, which rotatively drives a sprocket to advance the tape, and a communication unit for receiving a control signal from a control unit of an electronic component mounting apparatus and transmitting a control parameter such as a rotating speed, an amount of rotation, and acceleration and deceleration pattern to the motor controller. This makes the tape feeder of such a structure that a tape advancing speed and an amount of tape advancement are easily changeable according to a type of the electronic components by changing the control parameter of the rotating speed and the amount of rotation of the motor. In addition, the tape feeder is adaptable for correction of the amount of rotation according to a result of measurement of pin position of the sprocket, so as to properly interrupt turning of the sprocket at the correct stop position for accurate positioning of the electronic components into the right pick-up location at all the time.

FIELD OF THE INVENTION

[0001] The present invention relates to a tape feeder for feedingelectronic components borne on a tape by advancing them intermittentlyto a pick-up location in an electronic component mounting apparatus. Theinvention also relates to a method of advancing the tape.

BACKGROUND OF THE INVENTION

[0002] In an electronic component mounting apparatus, a tape feeder isused as a commonly known method of feeding electronic components into apick-up location of a nozzle of transfer head. In this method, a tapebearing the electronic components is pulled out of a supply reel, andfed to the nozzle by advancing it intermittently in synchronization withmounting timing of the electronic components. This tape feederintermittently advances the tape only for a predetermined amount byrotating a sprocket, which is in engagement with feedholes perforated inthe tape.

[0003] In using tape feeders, it is a general practice to prepare anumber of tape feeders of the same kind, and any of these tape feedersare mounted to a plurality of electronic component mounting apparatusesas needed. In other words, when taking a certain feeder mounting base ofthe electronic component mounting apparatus as an example, a number ofthe tape feeders that are adaptable for installation are mounted to it.These tape feeders supply electronic components to the transfer head byadvancing the tapes toward a pick-up location.

[0004] Because there are various types of electronic components havingdifferent sizes, it is necessary to prepare many kinds of tape feedersaccording to widths of the tapes that bear the electronic components aswell as mount pitches of the electronic components along the tapes.However, the conventional tape feeder requires a complicated work tochange a distance of advancement of the sprocket, when the tape requiresa different advancing pitch due to a difference in the type ofelectronic components even if the tape used has the same dimensionwidthwise. In addition, it is desirable to set an advancing speed andacceleration of the tape appropriately according to the type ofelectronic components, since there is a risk that the components becomeout of their normal positions and resulting failure of stable pick-up ofthe components depending on the type of electronic components and theoperation during advancement of the tape. However, it is not possible tomake such a setting of the tape advancing speed easily with theconventional tape feeders.

[0005] In many of these tape feeders, there are tape advancing errorsdue to individual instrumental errors, and a position of the advancedtape does not always come into alignment with the pick-up location ofthe transfer head. Mechanical adjustments are therefore necessary, suchas alignment of a positioning dowel for each of the tape feeders in theprior art techniques, and they require a great effort if many tapefeeders are involved.

DISCLOSURE OF THE INVENTION

[0006] In an electronic component mounting apparatus, a tape feedersupplies electronic components to a pick-up location by intermittentlyadvancing a tape bearing the electronic components, and that the tapefeeder comprises: a sprocket in engagement with feedholes perforated atregular pitches in the tape, for advancing the tape; a drive mechanismincluding a motor as a driving force for rotatively driving thesprocket; and a motor controller for controlling the motor. The tapefeeder further has any of the following features.

[0007] A) The tape feeder is provided with a communication unit forreceiving a control signal from an external device.

[0008] B) The tape feeder draws a data on an amount of rotation of themotor corresponding to a position where turning of the sprocket isinterrupted, based on a result of measurement of a pin position of thesprocket.

[0009] In a method of feeding electronic components using the tapefeeder provided with the above feature “A”, the tape feeder changescontrol parameter of the motor by communicating a control signal betweenthe motor controller for controlling the motor and a control unit in theelectronic component mounting apparatus during the step of advancing thetape intermittently by turning the sprocket with the drive mechanismhaving driving force of the motor.

[0010] A method of feeding electronic components using the tape feederof the above feature “B” comprises the steps of: measuring a pinposition of the sprocket when the sprocket is interrupted from turning,as an electronic component is advanced to a pick-up location; anddrawing a data on an amount of rotation of the motor corresponding tothe position where turning of the sprocket is interrupted, based on aresult of measurement of the pin position.

[0011] In addition, an electronic component mounting apparatus includesthe tape feeder provided with any of the above features “A” and “B”.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a side view depicting an electronic component mountingapparatus provided with a tape feeder according to an exemplaryembodiment of the present invention;

[0013]FIG. 2 is a side view depicting the tape feeder according to theexemplary embodiment of this invention;

[0014]FIG. 3 is a block diagram showing a structure of control system ofthe tape feeder according to the exemplary embodiment of this invention;

[0015]FIG. 4 is a partial side view depicting the tape feeder accordingto the exemplary embodiment of this invention;

[0016]FIG. 5A is a partial plan view depicting the tape feeder accordingto the exemplary embodiment of this invention;

[0017]FIG. 5B is an enlarged view of a part of FIG. 5A depicting a pinand the vicinity thereof;

[0018]FIG. 6A and FIG. 6B are tables respectively showing data on stopposition and data on pick-up location of the tape feeder according tothe exemplary embodiment of this invention; and

[0019]FIG. 7 is expository illustration showing a method of adjustingthe stop position and the pick-up location of the tape feeder accordingto the exemplary embodiment of this invention.

THE BEST MODES FOR CARRYING OUT THE INVENTION

[0020] First of all, a structure of an electronic component mountingapparatus is described with reference to FIG. 1. In FIG. 1, theelectronic component mounting apparatus 1 (hereinafter referred to as“mounting apparatus”) comprises component feeder unit 2 for supplyingelectronic components. The component feeder unit 2 has a plurality oftape feeders 4 mounted to a top surface of feeder base 3. Any of thetape feeders 4 pulls out carrier tape 7 bearing electronic componentsfrom supply reel 6 installed on truck 5 placed under the feeder base 3.The tape feeder 4 delivers the electronic components borne thereon to apick-up location of transfer head 8.

[0021] Head drive unit 11 actuates the transfer head 8, which thenmounts an electronic component picked up from the tape feeder 4 ontosubstrate 10 placed on conveyor track 9. Control unit 14 controls thehead drive unit 11. Storage unit 15 stores various data necessary forthe transfer head 8 to perform mounting operation and the tape feeder 4to perform advancing operation of the tape.

[0022] The data include tape data 15A, stop position data 15B, pick-uplocation data 15C, and mounting position data 15D, as shown in FIG. 3.

[0023] The tape data 15A represent such data as an advancing pitch andan advancing speed in advancement of the carrier tape 7 intermittently,an acceleration and deceleration pattern during the intermittentadvancement, and the like. These data are pre-set individually for eachkind of the carrier tapes 7.

[0024] The stop position data 15B is a correction data used to alleviatedeviation or displacement of a stop position of the tape in theintermittent advancement due to instrumental error inherent in each ofthe tape feeders. The electronic components borne on the carrier tape 7are precisely aligned to the pick-up location by making correction withthis data. In this exemplary embodiment, this correction is made ondeviation of the pin position of the sprocket that forwards the tape ina direction of the tape advancement.

[0025] The pick-up location data 15C is a data representing a pick-uplocation of the tape feeder 4 where the transfer head 8 sucks and picksup the electronic components. The pick-up location data is prepared inadvance for each of the tape feeders, so as to make correction of theinstrumental error inherent in each of the tape feeders. In thisexemplary embodiment, the correction is made on deviation ordisplacement in a direction orthogonal to the direction of the tapeadvancement among deviations in various directions of the pin positionof the sprocket, by aligning a pick-up location of the transfer head 8.

[0026] The mounting position data 15D is a data relating to coordinatesof a mounting position of the electronic component in the substrate 10.

[0027] Camera 12 is installed above the pick-up location of the tapefeeder 4. The camera 12 takes a photographic image of the pick-uplocation and the vicinity thereof, and recognition unit 13 performs arecognition process of the photographic image data. Through thisprocess, the recognition unit 13 discerns a location of a feedhole ofthe carrier tape 7, a pin position of the sprocket for advancing thetape, and the like, so as to detect an extent of deviation, ordisplacement, from the regular position. The control unit 14 calculatesstop position data and pick-up location data based on the amount ofdeviation of each of the pin positions as a result of detectiontransferred to the control unit 14. Referring now to FIG. 2, FIG. 3 andFIG. 4, tape feeder 4 will be described next. In FIG. 2, the tape feeder4 comprises main body 4A having a rectangularly slender shape andfixture unit 4B installed under the main body 4A. The main body 4A inmounted parallel to an upper surface of the feeder base 3, and thefixture unit 4B is positioned securely by engaging it to one end of thefeeder base 3. Feeder control unit 24 built into the main body 4A isconnected with the control unit 14 of the mounting apparatus 1 throughconnector 28 provided in the fixture unit 4B. The storage unit 15transfers to the feeder control unit 24 via the control unit 14, suchdata as the tape data 15A and the stop position data 15B that arenecessary for controlling operation of the tape feeder 4.

[0028] The tape feeder 4 is provided with sprocket 21 in the forward endof it. The sprocket 21 has pins 21A at regular pitches around itsperiphery for engagement with feedholes 7B (refer to FIG. 7) providedalso at regular pitches along the carrier tape 7 for advancement of thetape. In addition, the sprocket 21 is provided with toothed surface 21Bon the side of it (refer to FIG. 4) in engagement with bevel gear 23attached to a drive shaft of motor 22. The bevel gear 23 and the toothedsurface 21B compose a drive mechanism that drives sprocket 21.

[0029] The motor 22, when rotatively driven, turns the sprocket 21,which advances the carrier tape 7. This advancement pulls out thecarrier tape 7 from the supply reel 6. The pulled-out carrier tape 7 isguided into the tape feeder 4 from its rear end, and moved forward alonga tape-feeding passage.

[0030] The motor 22 used in this preferred embodiment is a type that iscapable of controlling a rotation speed and an amount of rotation, suchas a servomotor. An advancing speed and an advancing pitch forintermittent advancement of the carrier tape, a stop position during theintermittent advancement, and the like can be set freely as desired bycontrolling the rotation speed and the amount of rotation of the motor22. The motor 22 is also provided with an encoder with capability ofdetecting an absolute position, and it can detect individually arotational displacement of each of the pins 21A on the sprocket 21.There is a pick-up location in the forward end of the tape feeder 4,where the transfer head 8 picks up electronic components. The carriertape 7 guided here is advanced intermittently under cover plate 29placed on the upper surface of the forward end. The transfer head 8picks up electronic component 16 disposed in a recess 7A of the carriertape 7 through a cutout portion 29A in the cover plate 29 (refer to FIG.5A) between the intermittent advancements. Prior to picking up of theelectronic component 16, a cover tape (not show in these figures) ispeeled away from an upper surface of the carrier tape 7, pulled itbackward, and stored into a storage container (not show in the figures)housed in the main body 4A.

[0031] A control system of the tape feeder 4 is constructed as describednext with reference to FIG. 3. The tape feeder 4 contains feeder controlunit 24 built in it. The feeder control unit 24 is provided with motorcontroller 25, communication unit 27 and data storage unit 26. The motorcontroller 25 controls motor 22 for driving the sprocket 21. Thecommunication unit 27 receives a control signal from the control unit 14in the mounting apparatus 1, and transfers to the motor controller 25such control parameters as a rotation speed, an amount of rotation andthe like of the motor 22. Accordingly, the motor controller 25 changesadvancing speed, advancing pitch, and so forth of the tape feeder 4 fromtime to time according to a kind of carrier tape 7 used as directed bythe control unit 14.

[0032] In addition, the communication unit 27 performs a process ofwriting the data sent from the control unit 14 into the data storageunit 26. In regard to a command on control parameters to the motorcontroller 25, all what is needed is a simple command indicating a kindof carrier tape used, for the motor controller 25 to change theadvancing speed and the advancing pitch, if the data storage unit 26stores tape data 15A of that particular carrier tape.

[0033] According to this exemplary embodiment as described above, acontrol signal is transmitted from the external device to the motorcontroller which controls the motor, in the process of turning thesprocket and advancing the tape intermittently by the drive mechanismcapable of controlling the rotation speed and amount of rotation using amotor as the driving force. This structure makes possible to easilychange the advancing speed and advancing distance of the tape bychanging the control parameters such as the rotating speed and theamount of rotation of the motor according to the electronic componentsto be mounted. Therefore, the mounting apparatus is flexibly adaptableto the change of a type of electronic components it handles.

[0034] The stop position data 15B will be described next. In order todeliver electronic components 16 borne on the carrier tape 7 to theright position, the pin 21A is required to stop at the proper positionduring intermittent turning of the sprocket 21. However, there arecertain deviations in positions of the individual pins 21A of thesprocket 21 due to manufacturing error. It is therefore necessary tocorrect the deviations to bring each of the pins 21A into a stop at theright position. In this exemplary embodiment, the necessary correctionis made by using camera 12 to discern a position of each of the pins 21Aon the sprocket 21, and to obtain an amount of deviation in theposition.

[0035] The deviation in position of each of the pins 21A is measured ina manner as described hereinafter. FIG. 5A shows an upper surface of thecover plate 29 disposed above the sprocket 21. In FIG. 5A, dotted linesillustrate a tape bearing an electronic component in the deliveredposition. When the camera 12 takes a photographic image of the cutoutportion 29A without the carrier tape 7 set in position, it catches animage of one of the pins 21A located at or near a top area of thesprocket 21, and thus a position of this pin 21A is measurable.

[0036] The measurement gives pin offset data Δx and Ay representing adeviation of the pin 21A in the directions of X-coordinate andY-coordinate respectively from the regular position, as shown in FIG.5B. Offset data indicating a deviation of every one of the pins 21A fromthe regular position can be obtained in the same manner by measuring thedeviation of each pin one after another while turning the sprocket 21intermittently at intervals of a predetermined pitch. This can thus givea proper position of each of the pins 21A, that is, a stop positionwhere turning motion of the sprocket 21 is to be interrupted in theintermittent advancement of the tape, when each of the electroniccomponents comes to the right pick-up location. Calculation is now madeto obtain data for an amount of rotation of the motor 22 correspondingto each of the stop positions, as stop position data, and these stopposition data obtained here are stored as offset data peculiar to theparticular tape feeder 4. Accordingly, the motor 22 is controlled andits rotation interrupted based on the offset data, so as to stop thepins 21A at the right stop position at all the time when the tape feeder4 is under operation.

[0037] The control unit 14 performs a process of computation of thesedata in the mounting apparatus 1. Thus, the control unit 14 serves as astop position data-computing unit. A result of the computation is storedin the storage unit 15 of the mounting apparatus 1 as the offset datarepresenting amounts of positional deviations. At the same time, theseamounts of positional deviations are converted into another form ofoffset data with number of pulses representing amounts of rotation ofthe motor 22, and sent to each of the tape feeders 4. The data are hencewritten into the data storage unit 26 via the communication unit 27 ineach of the tape feeders 4. Accordingly, the storage unit 15 of themounting apparatus 1 and the data storage units 26 of the individualtape feeders 4 serve as stop position data storage units.

[0038] With reference to FIG. 5A through FIG. 6B, described nextpertains to modes of the stop position data and the pick-up locationdata. As described here, offset data in the direction of Y-coordinatecorresponds to the stop position data, and offset in the direction ofX-coordinate corresponds to the pick-up location data. In FIG. 6A,measurement is made on positions of all the pins 21A of the sprocket 21in the tape feeder, for which the data are to be prepared, and themeasured pin positions are processed statistically to obtain meanpositional data of the pin positions. In other words, mean values ΣΔx/nandΣΔy/n of the offset data Δx and Δy of the individual pins areobtained, and a mean value of them is used as a single offset datapeculiar to this particular tape feeder. Thus, the data processing canbe made easily by taking statistical process of the pin positional dataand obtaining only one offset data peculiar to that tape feeder.

[0039]FIG. 6B shows an example in which offset data is stored for eachof the pins 21A of the sprocket 21. That is, the offset data Δx and Δyare stored exactly as they are measured, in the storage unit 15 as theoffset data (i.e. stop position data 15B and pick-up location data 15C)peculiar to these particular pins 21A in this example. In theillustrated instance, the stop position data are produced for theindividual pins 21A with their deviations reflected as they are.Therefore, these deviations are corrected in order to make the carriertape 7 stop at the right position at all times even if there are largedeviations in the pin positions of the sprocket 21 due to manufacturingerror.

[0040] What has been discussed in this preferred embodiment is anexample, which uses distances of deviations of the pins 21A as the stopposition data. However, the stop position data can also be obtained bytaking a photographic image of an area in the cutoff portion 29A withthe carrier tape 7 set in position, and measuring either a position ofthe recess 7A or a position of electronic component 16 disposed in therecess 7A. Offset data Δx and Δy obtained in this case are distances ofdeviations of the electronic component 16 from the regular pick-uplocation.

[0041]FIG. 7 shows the method of correcting the stop position of thecarrier tape 7 based on the stop position data and the pick-up locationdata, as discussed above, with the tape feeder 4 in operation. To stopthe pins 21A of the sprocket, 21 at the right position duringintermittent advancing, the motor 22 is controlled according to theabove-mentioned stop position data for proper positioning. In otherwords, the motor 22 is stopped at a stop position corresponding to theposition where the correction is made only by a distance of the offsetdata Δy in the direction of Y-coordinate from the regular position inthe data (show with a dashed line in the figure), when interruptingrotation of the motor 22.

[0042] Following the above, the transfer head 8 is activated for pick-upoperation according to the pick-up location data when the electroniccomponent in the recess 7A is picked up with the transfer head 8. Thatis, the transfer head 8 is lowered after completing the positioning bycorrecting position of the transfer head 8 only by a distance of theoffset data Δx in the direction of X-coordinate from the regular pick-uplocation in the data. Accordingly, displacement of the pick-up locationdue to the deviations in the pin positions of the sprocket 21 can becorrected effectively. The invention accomplishes positioning of theelectronic component 16 into the right pick-up location, therebydecreasing pick-up errors by the transfer head 8.

[0043] According to this preferred embodiment, the tape feeder drawsdata on an amount of rotation of the motor corresponding to the rightposition where turning of the sprocket is to be interrupted, based onthe result of measurement of pin positions of the sprocket, stores thedata as the stop position data, and controls the motor based on theabove stop position data when the tape feeder is in operation. Thisstructure allows the sprocket to stop at the right stop position at alltimes, thereby achieving accurate positioning of the electroniccomponents into the right pick-up location, alleviating difficulties inthe positioning of the tape feeder, and improving the work efficiency.

What is claimed is:
 1. A tape feeder for feeding an electronic componentto a pick-up location in an electronic component mounting apparatus,said tape feeder comprising: a sprocket in engagement with feedholesperforated at regular pitches along a tape, for advancing the tapeintermittently; a drive mechanism provided with at least a motor forrotatively driving said sprocket; a motor controller for controllingsaid motor; and a communication unit for receiving a control signal froman external device, and transmitting to said motor controller a controlparameter of said motor.
 2. The tape feeder as defined in claim 1,wherein said control parameter includes at least one of data on a tapeadvancing pitch, an advancing speed, an acceleration and decelerationpattern during intermittent advancement of the tape, and an amount ofrotation of said motor corresponding to a stop position where turning ofsaid sprocket is interrupted.
 3. The tape feeder as defined in claim 1,wherein said motor controller is in communication with a control unit ofthe external device through a connector disposed to said tape feeder. 4.The tape feeder as defined in claim 1, wherein said drive mechanismcomprises: a bevel gear attached to a drive shaft of said motor; and atoothed surface formed on the side of said sprocket.
 5. A tape feederfor feeding an electronic component to a pick-up location in anelectronic component mounting apparatus, said tape feeder comprising: asprocket in engagement with feedholes perforated at regular pitchesalong a tape, for advancing the tape intermittently; a drive mechanismprovided with at least a motor for rotatively driving said sprocket; anda motor controller for controlling said motor, wherein said tape feederdraws a data on an amount of rotation of said motor corresponding to astop position where turning of said sprocket is interrupted, based on aresult of measurement of a pin position of said sprocket.
 6. The tapefeeder as defined in claim 5 further comprising a storage unit forstoring data on an amount of rotation of said motor corresponding to anactually measured data of the stop position, where turning of saidsprocket is interrupted, when the electronic component comes into saidpick-up location, said stored data being defined as an offset datapeculiar to said particular tape feeder.
 7. The tape feeder as definedin claim 5, wherein said data on an amount of rotation of said motor isobtained by statistically processing pin positions measured on all pinsof said sprocket.
 8. The tape feeder as defined in claim 5, wherein saiddata on an amount of rotation of said motor comprises individual pinpositions measured on all pins of said sprocket.
 9. A method of feedingan electronic component with a tape feeder, said method comprising thesteps of: transmitting a control signal from an external device to amotor controller for controlling a motor that drives a drive mechanism;changing a control parameter of said motor; turning with said motor, asprocket in engagement with feedholes perforated at regular pitchesalong a tape bearing the electronic component; and feeding theelectronic component to a pick-up location in an electronic componentmounting apparatus by intermittently advancing the tape.
 10. The methodof feeding an electronic component with a tape feeder as defined inclaim 9, wherein said control parameter includes at least one of data ona tape advancing pitch, an advancing speed, an acceleration anddeceleration pattern during intermittent advancement of the tape, and anamount of rotation of said motor corresponding to a stop position whereturning of said sprocket is interrupted.
 11. A method of feeding anelectronic component with a tape feeder, said method comprising thesteps of: advancing a tape bearing the electronic componentintermittently by rotatively driving with a motor a sprocket inengagement with feedholes perforated at regular pitches along the tape;measuring a position of a pin of said sprocket as said sprocket stopsturning when the electronic component comes to a position correspondingto a pick-up location in an electronic component mounting apparatus;obtaining a data on an amount of rotation of said motor corresponding toa stop position where turning of said sprocket is interrupted, based ona result of measurement of the pin position; and positioning theelectronic component into the pick-up location by controlling said motorand stopping said sprocket at the stop position according to said data.12. The method of feeding an electronic component as defined in claim11, wherein said data is obtained by statistically processing pinpositions measured on all pins of said sprocket.
 13. The method offeeding an electronic component as defined in claim 11, wherein saiddata represents a data common to every rotation stop position.
 14. Themethod of feeding an electronic component as defined in claim 11,wherein said data comprises data obtained individually for all pins ofsaid sprocket, as data peculiar to the corresponding pins.
 15. Themethod of feeding an electronic component as defined in claim 14,wherein said step of positioning the electronic component is carried outusing the individual data peculiar to the corresponding pins.
 16. Anelectronic component mounting apparatus comprising: a transfer head fortransferring to and placing on a substrate an electronic component froma tape bearing the electronic component; a control unit for controllinga head drive unit that drives said transfer head; and a tape feederhaving: a sprocket in engagement with feedholes perforated at regularpitches along the tape, for advancing the tape intermittently; a drivemechanism provided with at least a motor for rotatively driving saidsprocket; a motor controller for controlling said motor; and acommunication unit for receiving a control signal from said control unitof said head drive unit, and transmitting a control parameter of saidmotor to said motor controller.
 17. An electronic component mountingapparatus comprising: a transfer head for transferring to and placing ona substrate an electronic component from a tape bearing the electroniccomponent; a control unit for controlling a head drive unit that drivessaid transfer head; a tape feeder having: a sprocket in engagement withfeedholes perforated at regular pitches along the tape bearing theelectronic component, for advancing the tape intermittently; a drivemechanism provided with at least a motor for rotatively driving saidsprocket; and a motor controller for controlling said motor; and arecognition unit for discerning a pin position of said sprocket, whereinsaid apparatus draws a data on an amount of rotation of said motorcorresponding to a stop position where turning of said sprocket isinterrupted, based on a result of measurement of the pin position ofsaid sprocket discerned by said recognition unit.
 18. The electroniccomponent mounting apparatus as defined in claim 17, wherein saidapparatus makes correction of a location where said transfer head picksup the electronic component according to the result of measurement ofthe pin position of said sprocket discerned by said recognition unit.